Japanese Laid-Open Patent Application Publication H11- 12546, and its equivalent, U.S. Pat. No. 6,235,862, discloses a silicone adhesive sheet with protective films adhered to both sides of the sheet. The aforementioned sheet is intended for use as an adhesive means for attachment of semiconductor chips or chip supports. The protective films on both side of the aforementioned adhesive sheet are normally made from the same material.
However, if a cross-linked silicone adhesive sheet is made as a thin film with a thickness of 100 micrometers (μm) or less, conditions of peeling of the protective film from either side of the sheet become unstable.
It is an object of the present invention to provide an adhesive sheet of a cross-linked silicone characterized by stability of peeling of protective films from both sides of the sheet, as well as to provide an efficient method of manufacturing of the aforementioned adhesive sheet.